Monday, March 18, 2013

Controlling Bamboo

Bamboo is one of the most difficult plants to control. In fact, one of the best methods of control is prevention: do your homework before planting, learn about the different types and varieties and encourage your neighbors to do the same.

Homeowners with unwanted bamboo must be patient, as it requires an intensive control program which may last several years. Start with physically removing as much of the rhizome and root mass as possible, either by hand or with power equipment for larger areas.  If total removal is not possible, cut down the bamboo, wait for new growth to sprout, and then cut it down again, and again. Continue until no more shoots come up. Using this procedure, you are eventually exhausting the energy stored in the underground rhizomes. By constantly removing the foliage, you deny the plant the ability to photosynthesize and produce new energy so the rhizomes can no longer send up new shoots. If feasible, regular mowing will also work in this same manner, and over time the mowing will deplete the plant of energy.  Because bamboo is a grass, it can tolerate occasional mowing but does not tolerate frequent mowing. As much as two to three years of regular mowing may be needed in order to see results.

When controlling bamboo, it is often necessary to use herbicides.  Roundup (glyphosate) is one option for homeowners. It does not have residual soil activity and will kill only those plants that receive direct contact. First the bamboo must be cut, and then allowed to regrow until the new leaves expand.  Apply the herbicide at this point. Since Roundup does not translocate well to the rhizomes (i.e. transported from the leaves back down into the rhizome), the bamboo will likely re-sprout. Reapply Roundup whenever new growth is present.  It could easily take two years or more of this regime to attain control. Persistence is key.  

Another herbicide, Arsenal (imazapyr) is actually more effective than Roundup against bamboo.  The drawback is that unlike Roundup, imazapyr is soil active and will potentially kill other trees and shrubs and all grasses if their roots extend into the vicinity of the application. Therefore, if the bamboo is growing near any desirable plant species, Arsenal should not be used. As with all pesticides, the entire label ought to be read to make sure the material is being used in a safe manner, according to all label instructions.

If the bamboo in your yard has come from your neighbor’s yard, separate your ‘grove’ of bamboo from his by cutting the connecting rhizomes. They are usually quite shallow. If you don’t, your neighbor’s bamboo will continue to be a food source, providing energy to your bamboo and your efforts of cutting, mowing or spraying will be in vain. In addition, if not separated, any herbicide you apply has the potential of affecting your neighbor’s bamboo. To prevent a running bamboo from spreading, a barrier placed two to three feet deep in the soil can be effective. Barriers should be made of concrete, metal, or high density plastic. 

 In defense of this plant, bamboo can be a beautiful addition to a landscape. There are varieties of bamboo that do not spread out of control. Some varieties are even used for building, for furniture and for food.